We had troubling leaks with our forward hatch leaked as well.  Gaskets or bedding are generally the source.  After addressing the gasket issues, it still leaked, with water leaking out of the inner hatch trim strip.  I repeatedly tried Capt Tolley’s Creaping Crack Cure, as was suggested, but it didn’t work..  Finally I broke down and pulled the hatch.  I found that the screws Catalina used to install the hatch were too short, which caused quite a bit of flexing along the hinge line. The flexing was great enough to cause the fiberglass skin to de-laminate from the deck core. Catalina also didn’t seal the hatch mounting holes with epoxy to isolate the deck core from leaks, luckily the core was in good shape.   I ended up drilling holes, injecting epoxy, and c-clamping the de-lamination to repair it.  Finally re-bedded the hatch using longer 1 /1/2″ screws and Sikaflex 291